*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}

.nav-middle .welcome{
    font-size: 60px;
    color: #f4f4f4;
    position: relative;
    left: 50px;
    top: 20px;
}

.nav-middle .to{
    font-size: 50px;
    color: #f4f4f4;
    position: relative;
    left: 80px;
    top: 10px;
}

.nav-middle .jPetstore{
    font-size: 80px;
    color: #f4f4f4;
    position: relative;
    left: 50px;
}

li{
    list-style: none;
    float: left;
}

.arrowhead{
    font-size: 24px;
    text-decoration: none;
    display: block;
    text-align: center;
    width: 20px;
    height: 30px;
    line-height: 30px;
    background: rgba(158, 154, 154, 0.7);
    color: white;
    z-index: 999;
}

.left{
    position: absolute;
    top: 250px;
    left: 0px;
    border-top-right-radius: 15px;
    border-bottom-right-radius: 15px;
}

.right{
    position: absolute;
    top:250px;
    left: 530px;
    border-top-left-radius: 15px;
    border-bottom-left-radius: 15px;
}

.container{
    width: 550px;     /*容器大小要和图片大小保持一致。*/
    height: 550px;
    position: relative;
    left: 75px;
    overflow: hidden;
    margin: 50px auto;
    background-color: white;
    border: 1px solid black;
}

img{
    width: 550px;
    height: 550px;
}

.container .pic{
    width: 600%;
    position: relative;
}

.pic li {
    float: left;
}

/* 小圆圈 */
.lis{
    position: absolute;
    bottom: 15px;
    left: 50%;
    margin-left: -35px;
    width: 70px;
    height:13px;
    border-radius: 7px;
    background: rgba(158, 154, 154, 0.7);
}

.lis li {
    float: left;
    width: 8px;
    height: 8px;
    margin: 3px;
    border-radius: 50%;
    background-color: #fff;

}

.lis .selected{
    background-color: cyan;
}